Flashes and dark spots occur due to changes in the vitreous body, the clear, gel-like substance that fills the interior of the eyeball. As you age, this gel-like substance shrinks and gradually detaches from the inner surface of the eye. This shrinking and separation—or detachment—of the vitreous from the retina is common, especially in individuals over 50 years old. In nine out of ten cases, it does not cause any damage to the retina. This process is known as posterior vitreous detachment.
Flashes and floaters rarely lead to serious complications, so in general, no treatment is needed. If they are bothersome, the impact of these additional symptoms can be minimized by wearing dark glasses, which is especially helpful in bright sunlight or when looking at a bright surface.
In many cases, flashes fade over time and floaters become less noticeable as the brain adapts to the changes in the gelatinous substance. If flashes or floaters worsen, you should consult your doctor or optometrist. If you notice a dark shadow or curtain, or experience a sudden loss of vision, you should contact your doctor immediately.